Abstract
In vitro chemosensitivity of established cell lines from human prostate cancer (8 PC 93, 19 PC 93, DU 145 and PC 3) to various anticancer drugs was examined by clonogenic assay. The drugs used were aclarubicin (ACR), adriamycin (ADM), carboquone (CQ), vincristine (VCR), ifosfamide (IFM), peplomycin (PEP) and cis-platinum (CDDP). To compare antitumor activity of different drugs, the predicted anticancer activity (PAA) was calculated from the 50% inhibition doses and the peak plasma concentration of the clinically used dose. High antitumor activity of drug was considered if PAA 1 was observed. The chemosensitivities were: CQ>ADM>CDDP>VCR>PEP>IFM>ACR in the clonogenic assay. 19 PC 93 and DU 145 were sensitive to CQ, ADM and CDDP, but 8 PC 93 and PC 3 were sensitive to CQ, ADM, CDDP and VCR. Thus, a new combination chemotherapy with CDDP, ADM and CQ (PAQ therapy) was used clinically. PAQ therapy was given to sixteen patients with stage D advanced prostate cancer. Of these patients, 14 were undergoing relapse from antiandrogen therapy and 2 had hormone-resistant prostate cancer. The mean interval from the start of the prior treatment to relapse of the cancer was 18 months. The effectiveness of the new therapy was judged according to the response criteria for prostate cancer treatment of Japan. Three patients showed partial response (PR), 9 were stable disease (Stable) and 4 showed progressive disease (PD). The mean response duration in the patients with PR and with Stable was 11.6 months. The survival length of the responders (PR+Stable) was significantly longer than that of the nonresponders (PD) (p<0.001). The side effect of PAQ therapy was lower than the moderate degree.
Therefore, we considered PAQ therapy to be one of the clinical trials for the treatment of advanced prostate cancer.
